Dead-end strain carrier



Get. 6, 1953 c, HUBBARD 2,654,796

DEAD-END STRAIN CARRIER Filed Jan. 25, 1950 3 Sheets-Sheet l INVENTOR.

David Cjfubbaraf Oct. 6, 1953 D. c. HUBBARD 2,654,796

DEAD-END STRAIN CARRIER Filed Jan. 25, 1950 3 Sheets-Sheet 2 I 79 79 6 -1 V r I04 I .4 I '7 In I27 ize I I86" I l INVENTOR. Dcwui (I. Hubbard,

Patented Dot. 6, 1953 DEAD-END STRAIN CARRIER David C. Hubbard, Centralia, Mo., assignor to A. B. Chance Company, Centralia, Mo., a corporation of Missouri Application January 23, 1950, Serial No. 140,121

Claims. 1

The present invention relates to dead end strain carriers, and is particularly concerned with strain carriers to be used to relieve the load and take the strain off insulators on dead end constructions.

One of the objects of the invention is the provision of an improved strain carrier whichmay be used on poles, cross arms, steel towers, and which may be used with various difierent types of dead end clamps, various types of cradles for supporting the insulator, and also which may be used whether there are arcing rings or no arcing rings.

Another object of the invention is the provision of an improved tool of the class described, which is light in weight so that it is easy to carry to the top of the pole, simple to operate, strong in construction, and which is safe because of the safety lock for the conductor and because of the particular construction of the dead end clamp socket.

Another object of the invention is the'provision of an improved strain carrier of the class described, which can be used with less effort because the operator tightens only one pole at a time and pulls only half of the dead end load at one time, which can be mounted quickly and easily in practically all places desired, and which can be installed through arcing rings and will hold most dead end clamps or provide a place to attach wire grips.

Another object is the provision of an improved strain carrier in which the poles are free of bendin strain while they are being used because of the pivotal movement permitted between the yokes and the poles, thus making the strain carrier more safe because of the fact that the poles will not be broken by bending.

Another object is the provision of an improved, quick detachable means for holding one of the poles in place while the other pole is being in- Fig. 1 is a view in perspective of a complete strain carrier embodying the invention;

Fig. 2 is a similar view showing how the strain carrier may be used with the line pole inside its yoke, and showing a cradle for supporting the string of insulators;

Fig. 3 is a top plan view on a larger scale, showing the details of construction of the strain carrier;

Fig. 4 is a side elevational view taken from the right side of Figure 3;

Fig. 5 is a fragmentary sectional view taken on the plane of the line 55 of Figure 3, looking in the direction of the arrows;

Fig. 6 is a fragmentary sectional view taken on the plane of the line 6-6 of Figure 3, looking in the direction of the arrows;

Fig. 7 is a fragmentary sectional view taken on the plane of the line 1-1 of Figure 4, looking in the direction of the arrows;

Fig. 8 is a fragmentary sectional view taken on the plane at right angles to the view of Figure 7;

Fig. 9 is a top plan view of the attachment for engaging a dead end clamp;

Fig. 10 is a sectional view taken on the plane of the line Ill-l 0 of Figure 9; and

Fig. 11 is a side elevational view of the attachment of Fig. 9.

Referring to Figures 1 and 2, l0 indicates in its entirety the dead end strain carrier embodystalled on the yoke, and in which one pole is conveniently removed for storage.

Another object is the provision of an improved tool of the class described, which is adjustable in length and which is easily and quickly taken apart to be stored in a minimum amount of space so that the wood members may be protected against moisture or abrasion.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the three sheets of drawings accompanying the specification,

ing the invention, which includes a pair of insulating wooden poles II and I2. The poles II and I2 may be made of well seasoned laminated maple or spruce, and are preferably substantially cylindrical in shape and protected by an electrically insulated varnish.

The poles carry a pair of yokes of which I 3 is the. tower end yoke and I4 the dead end yoke, and the poles are provided with a multiplicity of regularly spaced partially circular peripheral grooves l5, which are provided over the major portion of the length of the two poles.

The grooves are not employed over an ungrooved portion l6 near the tower yokes as the length of this ungrooved portion represents a minimum length beyond which it is not desirable to go in bringing the yokes adjacent each other.

At the left end of the poles, Figure 1, each pole is provided with a cast metal ferrule l1, Figure 4, which comprises a cylindrical metal member having a cylindrical socket l8, of suflicient diameter to receive the end of the pole.

The ferrule I! has its end wall [9 provided with athrough bore 20 for receiving the shank of the take-up screw 2|, which screw has a head 22 of sufficient size to be received in the bore l6. Instead of a head the take-up screw 2| may be provided with a nut having a through pin 23, which also passes through the ferrule and secures the take-up screw 2| fixedly to the pole in axial position.

In other embodiments of the invention the ferrule |1 may be cast with a hexagonal socket in its end wall IQ for receiving the head of the take-up screw which may be confined in said socket by engagement with the end of the wooden pole.

The wooden pole is secured in the ferrule H by means of the transverse through pins 24, 25, the holes for which are drilled after the parts are assembled so that the pins and pole will be tight in the socket, and the pins are riveted over at each end.

The tower end yoke 13 comprises a cast metal member which is slightly arched so that it has a concavity at 26 on its inside and a hump at 21 on its outside, and the end portions 28 and 29 extend in a direction away from the hump 21.

The yoke l3 may have a central web 36, which is bordered on the outside by laterally projecting ribs 3|, and on the inside by laterally projecting ribs 32. The ribs 3| and 32 extend upward and downward with respect to the web 30, giving each edge portion a substantially T-shape.

At its center, inside the hump 21, the yoke |3 is provided with a slightly arcuate elongated through slot 33, which is bordered by the outwardly extending re-enforcing rib 34, on both sides of the yoke, and the rib 34 is connected to the border ribs 3| and 32 by integral formations 35, 36.

The formation 36 has a dead end bore 31, in which a conically pointed steel pin 38 is seated for engagement with a wooden pole. The elongated aperture 33 may be used for receiving a chain 33, Figure 1, which is provided with a hook 40, of the type having its slot just large enough to pass over one of the links of the chain 33. By means of the chain 36, the yoke i3 may be secured to poles, cross arms, towers, etc.

The hump 21 of this yoke is also preferably provided with an integral centrally located lug 4|, having a through bore 42, and adapted to serve for attachment of a clevis.

At each of its end portions 28, 23, the yoke I3 is provided with a socket 43, the details of which are shown in Figures 5, '1 and 8. The yoke may be of uniform thickness with respect to its border flanges 3|, 32, but it preferably has its web 30 tapered toward both end portions 26, 29, the border flanges approaching each other so that the yoke is of less thickness at its ends.

At each end the yoke has a pair of substantially solid end portions providing sufficient material for the sockets 43. Each socket has a flat bottom 44, Figure 8, the socket being located in the outer side of the yoke, and the socket may have outwardly spreading walls 45 on the sides toward which the take-up screw pivots.

The socket may have a pair of bearings for trunnions formed at 46 in the two diametrically opposite sides, the axis of these bearings being at right angles to the yoke l3. Below the socket 43, the end portion 29 of the yoke has a parallel sided slot 41, the two flat walls 46 of which are parallel to each other and spaced suillciently to pass the shank of the take-up screw 2|.

The take-up screw 2| is threaded over the major portion of its length so as to permit the take-up of substantially the full length of the screw, the unthreaded portion being only that which remains below the socket 43 when full takeup has been achieved.

The slot 41 preferably has its back wall 43, Figure 8, beveled toward the lower side to provide a maximum room for pivotal movement of the take-up screw 2|, with respect to the yoke. The two parallel side walls 43 of the slot 41 are formed on the laterally projecting lugs 50 of the end portion of the yoke, which provides sufiicient material for aligned through bores 5|, for receiving the threaded eye bolt 52 which is threaded into the bores 5|.

By having the eye bolt 52 threaded into both bores, which are tapped simultaneously, the eye bolt 52 may be withdrawn sufficiently to clear the slot 41, while still being held by the threads of the bore in the lug 50, which is nearest to the head of the eye bolt.

By providing the head of the eye bolt in the form of a circular eye 53, this member may be manipulated by means of a clamp stick when it is applied to an energized conductor. The shank of the eye bolt 52 passes across the slot 41, and effectively locks the take-up screw 2|, with its shank in the slot 41. This makes the device safe since the take-up screw cannot become detached from the yoke, even though the bearing member of the take-up screw gets out of the socket 43.

The take-up screw 2| in each case is provided with an apertured trunnion member 54, Figure '7, which has the cylindrical trunnions 55 to be received in the bearing portions 46 of the socket 43. Trunnions 55 are carried by a central body portion 56, the bottom of which has a pair of beveled surfaces 51, so that there is a maximum clearance between the bottom of the trunnion member 54 and the walls and bottom of the socket 43. This permits a maximum pivotal movement.

The body 56 is generally cylindrical at its upper part 56, and it has a flat annular thrust surface 56 surrounding a cylindrical core 60. The cylindrical core is of suflicient size to be received inside the cylindrical bore 6| of a ball bearing assembly 62, the lower surface of which rests upon the thrust surface or seat 59.

The ball bearing assembly 62 comprises upper and lower races 63, 64, each of which has an annular race or groove 65 semi-circular in cross section for receiving the balls 66. Any form of suitable ball bearing assembly may be employed.

The ball bearing assembly 62 is preferably of such a type that it is assembled as a unit, with its races secured together about the balls 66 so that the balls cannot drop out. The ball bearing assembly 62 is engaged on the outer surface of its race 63 by the take-up nut 61. This is a special nut having a threaded bore 66 and a relatively long hexagonal outer surface 69 for engagement with a ratchet wrench.

On its outer end the nut has an annular flange 16, which is relieved at 1| about the take-up screw 2|, and has an annular thrust surface 12 for engaging the ball bearing assembly 52. When the nut 61 is rotated, by means of a ratchet lever, the upper race 63 rotates with the nut while the lower race 64 remains fixed with the trunnion member 54.

The trunnion member 54 has a through bore 13 of suflicient size to provide a clearance about the threads of the take-up screw 2|. The construction of these parts is identical at both ends of the yoke I3, so that the take-up screw is mounted for pivotal movement on the trunnions 55, which have their axes at right angles to the general plane of the yoke I3.

When yoke I3 is combined with the poles II and I2, and the other yoke I4, these parts form a parallelogram which has pivots at its four corners so that strain is equally distributed between the two poles I I, I2 by virtue of the pivotal mounting of the yokes at the four corners, even though the nuts 61 are adjusted to unequal'positions on the bolts 2I.

Referring to Figures 2, 3, 5 and 6, the yoke I4 is the dead end yoke to which the energized conductor is to be attached. The yoke I4 is preferably constructed of two separate halves, the castings for which may be identical, but the halves of this yoke support different fixtures. The two halves are indicated by the numerals- 14 and 15.

Each of the halves preferably comprises an elongated cast metal member provided with a substantially straight, central body portion 16, with a pair of offsets 11, 18, adjacent each end, and with an enlargement 19 and 80 at each end that is provided with bearings.

The castings 14, are each preferably formed with a web 8|, Figure 3, bordered by the outwardly projecting border flanges 82, 83. The web tapers toward both ends so that the yoke castings are wider toward the center where the maximum strain is expected.

Like the tower end yoke I3, the yoke I4 is outwardly convex at 84, Figure 3, on its outer side and inwardly concave at 85 on its inner side, thereby tending to centralize the pull on a pole or other support.

The re-enforcing border flanges 82, 83 are joined by a central transverse re-enforcing flange 86, and the web may be thickened at four lugs 81, equally spaced from each other on opposite sides of the rib 86 to provide a stronger body at the point for the attachment of bolts.

The two halves may be secured together by means of a pair of screw bolts of the kind indicated at 88, Figure 6, which also support a tubular spacer 89 for holding the halves 14, 15 in spaced relation to each other. Only two bolts 88, with spacers 89, are preferably employed, both located on the same side of the center of the yoke in order to leave the central spa'ce90 between the halves of the yoke open for insertion of the energized conductor 9I from the opposite side, which opposite side is closed by a sliding locking arm pin 92.

The locking arm pin 92 comprises a steel pin, the extreme end of which is frusto-conical at 93, to guide it more readily into the apertures in the two halves. The pin slides into aligned apertures in the lugs 81, on the side opposite to the bolts 88, and is pivotally secured at its upper end to a locking arm 94.

The locking arm 94 comprises a cast metal member which is enlarged to a triangular shape to provide a circular aperture 95, large enough to receive the tool end of a clamp stick. From the aperture 95, the locking arm 94 tapers toward both ends and its free end 96 is curved inwardly toward the locking pin 92, to which it is secured by a rivet. The aperture for this rivet in the arm 94 may be a transverse slot, allowing a slight sliding movement at the pivot of the pin 92, since the pivot moves in a straight line. I

At its opposite end, locking arm 94 is pivoted by means of rivet 91 to bearing flanges carriedby a bolt 98. which is secured to the yoke'half 6 14 in a special socket provided for the head of the bolt.

The socket which is provided for the head of bolt 98, on yoke half 14, is utilized on yoke half 15 for supporting a pair of eye bolts 99, I00, the enlarged rings of which may serve as cradle hooks for receiving the wooden cradle rods IOI, I02, Figure 2. Eye bolts 99, I00, are, therefore, provided with larger eyes than those usually employed for a clamp stick connection, and the eye bolts are secured by nuts above and below the web BI of the yoke half 15.

The yoke castings 14, 15 are provided with offsets 11, 18, in order to provide parallel enlargements 19 and at each end, which are spaced sufficiently to pass the poles II and I2 as well as the pole clamps, by means of which the poles are attached to yoke I4.

The enlargements 19 and 80 of this yoke are also provided with laterally open slots I03, I04, like the slots 41 of Figure 5, to provide partially open bearings for the trunnions I05, I06 on the pole grippers. In this case, however, the slots are not provided with eye bolts 52, as shown in Figure 5, but are more readily detachable because the yoke halves are provided with the U- shaped retaining springs I01 on each of the ends of each yoke, the legs of the spring embracing the trunnions I 05, I06.

Springs I01 have a circular end portion which is secured by means of a screw bolt I08 to the yoke half. The two legs of the springs I01 are curved outwardly at I09 to provide a bell mouth into which the trunnions I05, I00 may be forced to be retained behind the curved shoulder IIO, on each leg of the spring.

The pole grippers II I are shown in elevation in Figure 6, and each of these may consist of a metal casting and they are identical in construction. Each pole gripper I I I has a half cylindrical body portion II2, which is integrally joined to a pair of parallel flanges II 3.

The flanges II3 support the oppositely extending trunnions I 05, I06, which are mounted in the open bearings I03, I04. The length of the cylindrical portion H2 is sufficient to span the space on the poles II and I2 between a pair of grooves I5, and the inside of the cylindrical portion H2 is provided with a pair of partially circular locking ribs II4, which are also circular in cross section to fit in a pair of grooves I5 on the poles II and I2. Thus the locking ribs II4 prevent the pole grippers from sliding longitudinally on the pole except when the pole is moved away from the cylindrical portion II2 with the ribs II4 out of the grooves I5.

The parallel flanges II3 of the pole grippers III are each provided with the inwardly extending flanges I I5 joined by an integral yoke H6 that has a threaded bore II! for the eye bolt II8. Eye bolt II8 ends in a ring II9, large enough to be grasped by means of a clamp stick, and at its opposite end the eye bolt has a reduced cylindrical portion I20, rotatably mounted in a sliding shoe I2 I.

The sliding shoe I2I comprises a cast metal member of partially cylindrical form and of sufficient Width to slide. between the flanges H3. Shoe I2I has a central bore I22 for receiving the reduced end I20 of the eye bolt I I8, this end being spun outward in a countersunk portion I22, so that the eye bolt is rotatably mounted with re spect to the shoe.

The inner cylindrical surface I23 of the shoe again has a pair of locking ribs I24, complemental-y in shape to the grooves I for engaging in the grooves I5 on the side opposite to the rribs II4. Thus the shoe 'I-2I may be advanced or retracted by means of the eye screw II8 to grip or release the poles II and 12.

The pole clamp -I-I-I preferably has its body in the shape of relatively thin body flanges re-enforced by a multiplicity of external re-enforcing ribs I25, Figure 3, these ribs appearing about the periphery of the pole clamp at each end and also converging toward the trunnions as seen in Figure 3.

IYhe border flange 83 on the halves of the yoke I4 is of course interrupted at the slots I03, I04 so as to leave this side of the bearing open for entrance of the trunnions I05, I05, which are resiliently gripped by the springs I01.

One pair of trunnions, such as, for example, the trunnions at the right end of yoke I4, in

Figure 3, may be provided with .an enlarged washer I26, too big to pass the opening between the ends of the border flange 83, at slot I04, and with a through cotter .pin I21 in each of the trunnions outside the washer I25. Thus the right end of the yoke I4 is permanently pivoted to the pole clamp and pole H at that end, while the leftend of yoke I4 is quickly detachable from its pole clamp by springs I0 1.

The yoke halves 14, are each provided with a central inward bearing flange I28, Figure 3, having aligned apertures I29 serving as bearings for trunnions I30, carried by a dead end conductor engaging fixture I3I. The details of construction of this conductor engaging fixture or attachment ar shown in Figure 9, which consists of a member which is substantially recta-ngularin side elevation, as seen in Figure 3, and is provided with the laterally projecting trunnions I30 for engagement in the bearings I29 of the yoke -I4.

On its upper surface, in Figure 3, the attachment I3I is formed with a frusto-conical surface I32 surrounding the circular portion I33 of a laterally open slot I34. The round portion I33 of slot I34 is gradually curved on its lower side, as indicated by the dotted line I35, so that there ar no sharp corners engaging the conductor. Lugs I48 urge clamp I41 into socket I32.

The attachment I3I is placed in its bearings with the slot I34 opening toward the pole I2, since this is the pole that is removed in applying the carrier to an energized line.

Referring to Figure 2, this shows one type of cradle that may be employed when a string of insulators is to be removed. This cradle has a pair of wooden rods IOI, I02 which are held in spaced relation by curved, transverse frame members I36 that have clamping rings I31 provided with screw bolts I38 at each end. A third transverse frame member I39 has tubular extensions I40 on its clamping rings, and the tubular extensions have transverse apertures mounting the metal rods I41 and I42 which diverge to engage hooks I43 on each of the poles.

The hooks I43 are partially circular and complementary to the outside of poles II and I2, and have enlargements I44, with through bores for the rods I4I, I42. Set screws I45 extend into threaded bores in the enlargements I44 and clamp the rods MI and I42.

At the yoke I4 the cradleis supported by means of the enlarged eyes 99, I00. .At the opposite end the cradle is supported by means of the hooks I43 on the poles H and 12.

Referring to Figure 2, this figure shows the strain carrier in position .to take thestrain which is present in the conductor-BI by reacting against the .line pole 146. The conductor 9I .isheld by means =of the .dead end .clamp I41, which has been detached from itsanchorageon the :pole or cross arm, and the left .end of the clamp I41 is seatedinthetapered-concavity of the attachment I3 I.,.carried by the innersideof the yoke .I4.

The methodof manipulation and the mode of operation of the strain carrierisas follows:

The .poleclamps III are first set to engage the selected grooves IS on the poles .so that the assembly will be of .the proper length to permit a take-up of the tension .by means .of the take-up screws III .and nuts -61, when the other yoke I3 has been engaged with .thepole, cross arm or the like.

The pole I2 is disengaged from the yoke I3 at its upper end, Figure 3, by unscrewing the eye screw 52 .to such a point .that it is held only by the left hand flange 50, clearing the slot so that the take-up screw 2| may move out of the slot of the yoke 13. The take-up nut 51 on each of the oles II and .12 isbacked oif to allow the trunnions v55 to clear their recesses, and also .to permits. maximum amount of threaded adjustment of the nut when the take-up is to be .later accomplished.

The pole II is also removed from the yoke I3 in the same way, and the .pole II is to be used in manipulating the yoke I4, which is to be engaged with an energized conductor.

The yoke I3 may then be chained behind a line pole, cross arm or tower arm, or it may be chained in position resting atop a cross arm or tower arm, 'or it may be secured by means of a strain jack or other pulling device attached to the lug -4I.

First the pole I2 is also disengaged at its lower end from theyoke I4 by pushing downward in Figure 3 until the trunnions pass out of the springs I01, and out of their bearings while permitting the hump I84 .of the yoke Hi to react against some fixed member .during this detachment. This opens the left endof the yoke I4 so that the conductor may have access to the space between the yoke halves 14, -15, Figure 6.

A second operator may engage the eye in the lever 04 with a clamp stick and by pivoting the lever 34 clockwise, in Figure 6, the pin 92 is removed from its looking position so that a conductor 9| may move :into the central space between the halves 14, 15 of the yoke I4, where it is to be secured.

With the yoke I4 in this open condition, still secured to the pole .I I,.the operator may grasp the free end, that .is, the upper end, in Figure 3, of pole Ill, and he may extend the yoke beyond the insulators and beyond the dead end clamp to move the two halves 14, 15 of the yoke I4 over the conductor into the space shown for the conductor 9| in Figure 6.

As soon as this has been accomplished the operator who has hold of the lever '94, by means of a clamp stick in the hole 95, should pivot the lever 94 counterclockwise to drive the pin 92 into the locking positionshown in Figure 6.

The yoke 14 is now locked upon the conductor at a point beyond the-dead end clamp, and is held by the operator bymeansof pole I I. The clamp stick should then be removed from the lever 94. At this time the conductor BI is also located in the slot I34 of the attachment I3I, Figure 3, Figure 9.

.Theqperatormay then move the yoke I4 backward against the dead end clamp, seating the dead end clamp in the tapered recess I32 of the attachment I3I. The frusto-conical nature of the recess I32 tends to center the end of the dead end clamp in this socket, also centering the conductor in the rounded portion I33 of slot I34.

The dead end clamp is seated in socket I32 behind the trunnions I30, that is, to the left in Figure 9, and this tends to keep the attachment I3I in proper alignment with the line or pull. In other words, the socket I32 is deeper than the axial line through the trunnions I30 so that a .stable condition exists in the engagement of the dead end clamp with the pivoted attachment I3 I.

With the pulling yoke I4 in position the operator then secures the pole I2 to the yoke I4 by grasping the take-up screw end of the pole I2, .and moving the pole clamp III between the halves I4, it of yoke I4 until the trunnions I can be moved into the slot I03 and into the space .between the springs II]? where the trunnions are grasped by the springs.

Tne two operators who are holding the device by means or its insulated poles II and I2, may then reattach the take-up screw ends of the poles II and I2 to the yoke I3, which has been previously secured to some fixed abutment, such as a .line pole. This is done by passing the take-up .screws into the slots 41 and arranging the trunnions 55 so that they rest in their bearings 46 in .the yoke I3.

The take-up screws 2i are locked in the slots 41 by means of the eye screws 52, which are screwed in until they engage and pass through the opposite flange 50 and are preferably driven .home until the flange below the eye is against the adjacent flange 50.

The take-up nuts 67 may then be turned by hand on the take-up screws 2 I, until all the slack .is taken up in the tool setup. Thereafter a wrench is applied to the nuts 61, such as a ratchet .socket Wrench, and the nuts 67 are driven downward on the take-up screws 2I, Figure 3, until all of the strain is taken off the dead end insulators and the tension of the line conductor is borne by .means of the dead end clamp, engaging the yoke l4, which in turn is supported b the poles II and I2 and yoke I3.

As to the operation of the tool, either nut may be tightened on either pole II or I2 as much as desired, as it is not necessary to take up both poles equally since the poles have pivotal engagement at each of the four corners of the strain carrier frame, that is, at the end of each yoke.

If the insulator in question is a string insulator the cradle may be attached to the present tool, as shown in Figure 2, to provide support for the insulator while it is being removed. When the conductor is again to be attached to the insulator attachment is made from the insulator to the dead end lamp and then the nuts 61 are backed off by means of a wrench until the strain is taken by means of the dead end clamp and insulator. Then the nuts 61 may be backed off by hand until the trunnions 55 can be moved out of their bearings in the yoke I3, the eye screws 52 are backed off to open the slot 41 and the poles are detached from the yoke I3, which is then removed from the support to which it was chained.

The pole I2 is then removed from the yoke I4 by pushing on the pole I2 while holding the yoke I4 by means of a clamp stick, the springs I01 releasing the trunnions I05, the removal of the pole I2 opens the space between the halves I4, I5 at one end.

The locking pin 92, Figure 6, may be pulled out by using a clamp stick attached at the hole to lever 84, thereby unlocking the yoke It with respect to the conductor 9|. Using the pole II as a handle the yoke I4 may then be moved off the conductor, being first backed away so that the dead end clamp I4! is disengaged from the socket in the attachment I3 I.

It will thus be observed that I have invented an improved dead end strain carrier having the following advantages:

(1) The poles are pivoted at the four points of their engagement with the yokes so that no bending strains are placed on the poles.

(2) No bending strains are placed upon the poles by their use in installations where there are deep sagging angles or on ridge top locations.

(3) Either screw may be entirely taken up without manipulating the other take-up screw nut, and the tool cannot be overstressed by improper take-up procedure.

(4) The amount of weight handled by an operator is greatly reduced and the strain carrier may be installed on insulator strings without removing arcing horns or gradient rings.

(5) The tool may be used with or without separate take-up jacks and when the latter is used the travel can be increased sufficiently to add insulators or remove them from the string where the transmission voltage is increased or decreased.

(6) The torsional strain on the take-up screws and the effort required are reduced by the use of ball bearings.

('7) The tool is locked on the conductor and the latch is automatically released when the lift eye is used to remove the yoke from the line conductor.

(8) The present tool may be taken apart so that it can be stored in a minimum space, and it may be provided with interchangeable clamp sockets so that its range of use may be greatly extended over the devices of the prior art.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a dead end strain carrier, the combination of a pair of elongated cylindrical wooden insulating poles, said poles each having a tubular fixture carried by one end, and provided with an axial threaded bolt, a metal yoke provided at each of its ends with an upwardly open slot for receiving said bolts between a pair of legs, a threaded pin located in aligned apertures in said legs to hold the bolts in said slots, a trunnion member reacting against a nut on each bolt and having a bore surrounding each bolt, and having a pair of trunnions receivable in a pair of half bearings formed in said yoke adjacent each of said slots, said trunnions and half bearings having their axes at substantially right angles to the plane of said poles, means for pivotally securing said yoke to a line pole midway between the ends of the yoke, and means carried by said insulating poles for securement to a line conductor.

2. In a dead end strain carrier, the combination of a pair of elongated cylindrical wooden insulating poles, said poles each having a tubular fixture carried by one end,- and provided with an axial threaded bolt, a metal yoke provided at each of its ends with an upwardly open slot for receiving said bolts between a pair of legs, a threaded pin located in aligned apertures in said legs to hold the belts in said slots, a trunnion inenib'er reacting against a nut on each bolt and having a bore surrounding each bolt, and having a pair of trunnions receivable in a pair of half bearings formed in said yoke adjacent each of said slots, said trunnions and half bearings having their axes at substantially right angles to the plane of said poles, means for pivotally securing said yoke to a line pole midway between the ends of the yoke, and means carried by said insulat ing poles for securement to a line conductor, a cradle for an insulator, comprising a pair of insulating wooden poles, transverse frame members securing the latter poles in parallel position, and means for hanging said parallel poles below and between the first-mentioned poles.

3. In a dead end strain carrier, the combination of a pair of elongated cylindrical wodden insulating poles, said poles each having a tubular fixture carried by one end, and provided with an axial threaded bolt, a metal yoke provided at each of its ends with an upwardly open slot for receiving said bolts between a pair of legs, a threaded pin located in aligned apertures in said legs to hold the bolts in said slots, a trunnion member reacting against a nut on each bolt and having a bore surrounding each bolt, and having a pair of trunnions receivable in a pair of half bearings formed in said yoke adjacent each of said slots, said trunnions and half bearings having their axes at substantially right angles to the plane of said poles, means for pivotally securing said yoke to a line pole midway between the ends of the yoke, means carried by said insulating poles for securernent to a line conductor, a cradle for an insulator, comprising a pair of insulating wooden poles, transverse frame members securing the latter poles in parallel position, and means for hanging said parallel poles below and between the first-mentioned poles, comprising a pair of diagonally extending rods carried by collars on said first-mentioned wooden poles.

4. In a dead end strain carrier, the combination of a pair of elongated cylindrical wooden insulafing poles, said poles each having a tubular fixture carried by one end, and provided with an axial threaded bolt, a metal yoke provided at each 'of its ends with an upwardly 'open slot for receiving said bolts between a pair of legs, a threaded pin located in aligned apertures in said legs to hold the bolts in said slots, at trunnion member reacting against a nut on each bolt and having a bore surrounding each bolt, and having a pair of trunnions receivable in a pair of half bearings formed in said yoke adjacent eachof said slots,'s'aid trunnions and half bearings having their axes at substantially right angles to the plane of said poles, means for pivotally securing said yoke to a line pole midway between the ends of the yoke, means carried by said insulating poles for 'securement to a line conductor, a cradle for an insulator, comprising a pair of insulating wooden poles, transverse frame members securing the latter poles in parallel position, means for hanging said parallel poles below and between the first-mentioned poles, comprising a pair of diagonally extending rods carried by collars on said first-mentioned wooden poles, said yoke having an enlarged 12 secret at e ch end surrounding the closed end of each of said slots for receiving said trunnion member and permitting maximum pivotal movemeat.

5. In a dead end strain carrier, the combination of a pair of elongated cylindrical wooden insulating poles, said poles each having a tubular fixture carried by one end, and provided with an axial threaded bolt, a metal yoke provided at each of its nds with an upwardly open slot for receiving said bolts between a pair of legs, a threaded pin located in aligned apertures in said legs to hold the bolts in said slots, a trunnion member reacting against a nut on each bolt and having a bore surrounding each bolt, and having a pair of trunnions receivable in a pair of halt bearings formed in said yoke adjacent each of said slots, said trunnions and half bearings having their axes at substantially right angles to the plane of said poles, means for pivot-ally securing said yoke to aline pole midway between the ends of the yoke, means carried by said insulating poles for securernent to a line conductor, and said latter means comprising a line conductor clamp carried by a second yoke adjustably secured to said first-mentioned wooden poles.

6. In a dead 'end strain carrier, the combination of a pair bi elongated cylindrical wooden insula'ting poles, said poles each having a tubular fixture carried by one end, and provided with an axial threaded bolt, a metal yoke provided at each of its ends with an upwardly open slot or receiving said b'olts between a pair of legs, a threaded pin located in aligned apertures in said legs to hold the bolts in said slots, 2. trunnion member reacting against a nut on each bolt and having a bore surrounding each bolt, and having a pair or truhnions receivable in a pair of half bearings formed in said yoke adjacent each of said slots, said trunnions and half bearings having their axes at substantially right angles to the plane of said p'oles, means for pivotally securing said yoke to a line pole midway between the ends of the yoke, means carried by said insulating poles for securement to a line conductor, comprising a second yoke having a pair of substantially parallel frame members secured together in spaced relation to each other to receive the line conductor between them, half bearing slots formed in each of said parallel members at each or their ends, and a cylindrical clamping member having a pair of trunnions to be received in said bearing slots, said clamping members having a fixed cylindrical clamping "surface, and a movable part cylindrical clamping member actuated by an eye screw.

7. A yoke for a dead end strain carrier, comprising a pair o f'm'etalinembers, each having hvo angular portions joined at an obtuse apex, said metal members being secured together by spacers and through s'e'curing members adjacent said apex in substantially parallel position, for receiving a line conductor between them, a lever pivotally mounted on one of said members on the outer side thereof, and having a pointed "plunger pivotally mounted on the end of the lever to slide into apertures in said members on the other side of the apex, for confining the line conductor by means of said plunger, said lever having an eye opening between its ends so that, when the yoke is lifted b'ymeans of a clamp'stick applied to said eye opening, the .phmger is withdrawn to receive said line conductor, and when the clamp stick :is removed, the plunger drops by gravity into said apertures, confining the line conductor between said members.

8. A yoke for a dead end strain carrier, comprising a pair of metal members, each having two angular portions joined at an obtuse apex, said metal members being secured together by spacers and through securing members adjacent said apex in substantially parallel position, for receiving a line conductor between them, a lever pivotally mounted on one of said members on the outer side thereof, and having a pointed plunger pivotally mounted on the end of the lever to slide into apertures in said members on the other side of the apex, for confining the line conductor by means of said plunger, said lever having an eye opening between its ends so that, when the yoke is lifted by means of a clamp stick applied to said eye opening, the plunger is withdrawn to receive said line conductor, and when the clamp stick is removed, the plunger drops by gravity into said apertures, confining the line conductor between said members, said yoke members each being formed with laterally open bearing slots at their ends, and a clamping member having trunnions mounted in said bearing slots, said clamping member comprising two partially cylindrical jaws with an eye screw to control their relative movement so that cylindrical wooden poles can be placed in said clamping members and clamped by actuating said eye screw with a clamp stick.

9. A yoke for a dead end strain carrier, cornprising a pair of metal members, each having two angular portions joined at an obtuse apex, said metal members being secured together by spacers and through securing members adjacent said apex in substantially parallel position, for receiving a line conductor between them, a lever pivotally mounted 101']. one of said members on the outer side thereof, and having a pointed plunger pivotally mounted on the end of the lever to slide into apertures in said members on the other side of the apex, for confining the line conductor by means of said plunger, said lever having an eye opening between its ends so that, when the yoke is lifted by means of a clamp stick applied to said eye opening, the pliuiger is withdrawn to receive said line conductor, and when the clamp stick is removed, the plunger drops by gravity into said apertures, confining the line conductor between said members, said yoke members each being formed with laterally open bearing slots at their ends, and a clamping member having trunnions mounted in said bearing slots, said clamping member comprising two partially cylindrical jaws with an eye screw to control their relative movement so that cylindrical Wooden poles can be placed in said clamping members and carlriiped by actuating said eye screw with a clamp s 10 10. A dead end strain carrier adapted to be manipulated by mean-s of a clampstick or other insulating pole, comprising a pair of cylindrical insulating poles, each of said poles being provided with one of its end portions formed with a plurality of spaced peripheral grooves, and the other of its end portions provided with a longitudinally extending threaded bolt, a transverse yoke member for the bolt end of said poles, said yoke member being provided at each end with a lateral open socket for receiving said bolt, and the lateral opening of each socket terminating in a pair of parallel flanges, one of which is threaded, and the other of which is apertured, for receiving a threaded eye bolt for confining the pole bolts in said sockets, each of said pole bolts being provided with a nut and with a trunnion member having a pair of oppositely located trunnions mounted in partially cylindrical bearings :formed in the outer sides of said sockets, the said nuts being adjustable on said pole 'bolts for adjusting the length of the strain carrier in smaller increments than the spacing between said grooves, a second yoke comprising a pair of parallel members secured in parallel relation to each other, and each being provided at each of its ends with partial bearings facing outwardly for receiving trunnions, the said trunnions being carried by a trunnion member extending about said poles, and each of said latter trunnion members being provided with a clamping member actuated by an eye bolt, said clamping member being provided with ribs receivable in said grooves, and all of said trunnions extending in a direction at substantially right angles to said poles and yokes, thereby providing a four sided frame, the sides being pivoted together at each corner for equalizing the strain on both poles and substantially eliminating any bending strain on the poles.

DAVID C. HUBBARD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,940,162 Bodendieck Dec. 19, 1933 2,162,070 Dunaway et a1. June 13, 1939 FOREIGN PATENTS Number Country Date 363,952 England Dec. 31, 1931 551,379 Germany June 7, 1931 

